Decalcomania for decorating ceramic ware

ABSTRACT

Improved decalcomanias suitable for high rate application to substrates and for the decoration of ceramic ware and the like contain a layer having low adhesion to a carrier layer, so that the carrier layer is readily removable after application of the decalcomania to a substrate. The desired low adhesion is achieved by the introduction of wax into the decal layer or by incorporating oil in a preprint lacquer layer between the decal layer and the carrier.

United States Patent Kluge et al. July 8, 1975 [54] DECALC M FORDECORATING 3,043,732 7/1962 Shepherd 156/230 CERAMIC WARE 3,445,3095/l969 Milliken 156/240 3,480,500 ll/l969 Hotter l56/233 [75] Inventors:Karl-Heinz Kl g M n Alfr 3,616,015 10/1971 Kingston 156/230 Eppich,Zirndorf, both of Germany [73] Assignee: F. Xavier Leipold, Zirndorf,Primary n rge F- Lesmes Germany ASSIISZGHZ Examiner-James Attorney,Agent, or Firm-Blum Moscovitz Friedman [22] Filed: Apr. 24, 1972 &Kaplan [21] App]. No.: 246,964

[57] ABSTRACT [52] 428/40; 156/230; lmproved decalcomanias suitable forhigh rate applil56/240' 427/147;.428/348; 428/350* cation to substratesand for the decoration of ceramic 2 428/352 428/484 428/486 ware and thelike contain a layer having low adhesion Cl- 1 to a carrier y so h thecarrier layer i readily Field of Search movable after pp c 0f the eca ao a 156/230 substrate. The desired low adhesion is achieved by theintroduction of wax into the decal layer or by incorpo- [56] ReferencesC'ted rating oil in a preprint lacquer layer between the decal layer andthe carrier 2,970,076 1/1961 Porth l56/240 3,007,829 ll/l96l Akkeron156/230 10 Clam, 3 Drawmg Flgures 6 flDi/ES/V' L/M'GUEB 7-- SCQEE/V PZ/N7'50 COL 0e PPM 7 w/n/ M/b- 5/ \OF/SETOE FZfiTPW/A G #0055 0564i 1 4/161? W/7'A/ Dexnenv C047 7 C010/? Rem r W/m/ W44 PP0Vf M64052 F "05044pnflee IMPROVED DECAL COMANIA FOR DECORATING CERAMIC WARE BACKGROUND OFTHE INVENTION In the decoration of ceramic, porcelain, enamel andglassware, the method of wet decalcomania designs has been widely used.Wet transferable ceramic decalcomania pictures are essentially of thefollowing structure:

On a special paper which is permeable to water and which is coated withdextrin or glue or other adhesive substances, a picture is printed usingceramic pigments. For the printing, a variety of processes may be used,such as, lithoprinting, off-set printing, screen-printing and othermethods which are more or less standard. The color print containing theceramic pigments is, at the present time, in most cases overprinted bythe screen-printing with a film lacquer, thereby forming the so-calledfilm-lacquer mask". This film-lacquer mask in the form of a foil on thecolor print gives to the design the cohesion required for the latertransfer step. To effect the transfer, the decalcomania is wetted. Waterpenetrates the paper from the rear softening the layer of dextrin orother adhesives on the inner surface of the paper. The design is therebyreleased and the decalcomania is then placed against the article to bedecorated. The film mask, of course, is transferred with the ceramiccolor print to the article with the film mask away from the articleitself. The foil picture is then firmly pressed by means of a rubberroller against the substrate to eliminate water from therebetween.

After a period of preliminary drying, the ceramic articles are placedinto a decoration furnace. During the earlier stages of the bakingprocess, the organic components of the film mask and the printing mediumare burned away. The temperature is then raised sufficiently to causethe vitrifiable pigments to flow and ad here to the substrate.

For the making of picture prints, off-set varnishes on a linseed oil oran artificial resin base are used while for the ceramic color-screenprints, screen-printing oils are used. Components in these oils areacrylic resins, ethyl cellulose, celluloseacetobutyrate, or other knownsynthetic resins which are compatible with the oil used.

The solutions of which the film masks are formed,

contain material such as acrylic resins, ethyl cellulose,

cellulose acetobutyrate, cellulose nitrate, or other resins of similartypes.

Although excellent decorative effects have been achieved by means of thewet decalcomania transfer process, it has not as yet been found possibleto automate the process so that considerable labor of relatively highskill is involved. The costs of decalcomania supplied as described aboveare relatively high.

Another technique for the decoration of ceramic ware and the like is theso-called heat release process which involves the use of a special papercoated on one surface with a uniform wax layer. The preferred printingprocess for use with the wax paper carrier is screenprinting.Unfortunately, it has been found that screenprinting directly on the waxlayer is not feasible. Consequently, it is necessary to coat the waxlayer first with a preprint lacquer. This preprint lacquer is necessaryso that during the heat-transfer process of applying the decalcomania tothe substrate, the color print, also termed the decal layer, will befully transferred to the article. As in the wet method described above,it is desirable that the decal layer containing the ceramic vitrifiablepigment be overprinted by the screen-printing method with athermoplastic finishing varnish; this varnish provides the necessaryadhesion to the substrate.

In making the transfer by which the finishing varnish holds the decalsto the substrate, the heat can be provided either by pre-heating theceramic article (as when it is decorated before cooling completely onleaving the kiln) or by heating the exterior of the decalcomania. Usingeither method of heating the assembly, the wax layer located between thepaper and the preprint lacquer melts and releases the picture from thepaper so that the paper can be removed.

It was hoped that it would be possible to automate the transfer ceramicpictures by the introduction of the wax-paper method. Unfortunately,however, these ex pectations have not been fulfilled for the followingreasons:

1. The production of a decalcomania based on a waxpaper carrier hasproved to be expensive.

2. The printing of a design on paper coated with wax has proved to beextremely difficult.

3. The mechanical transfer of decals to ceramic articles could not becarried out at a sufficiently high rate.

This last difficulty is due to the fact that the speed of the stroke ofthe transfer machines for wax-paper pictures is dependent on the timeinterval which is required in order to melt the wax layer between thedesign and the paper. Only after melting the wax can the paper be liftedoff the design which, in the meantime, has adhered to the ceramicarticle.

SUMMARY OF THE INVENTION Release of a layer containing vitrifiablepigments in the form of a decoration from a carrier is provided for byincorporating a material in a layer other than the carrier itself whichweakens the bond between the pigment-containing layer and whatevercarrier is used. In one embodiment, the pigment-containing layer itselfhas incorporated therein a high molecular weight wax which weakens thebond between said layer and a support layer, whether the support layeris the carrier itself or an intermediate layer. In a second embodiment,a preprint lacquer layer containing oil is interposed between thepigment-containing layer and the carrier. Enough oil is incorporated inthe preprint layer so that the bond between the preprint layer and thecarrier is weak. The carrier may be a paper having a dextrin or gluelayer thereon or even a metal foil.

[t is preferable though not necessary that the pigment-containing layerbe coated with a thermo-active layer, i.e., a layer containing athermo-plastic resin which becomes tacky when heated.

Accordingly, it is an object of the present invention to provide animproved decalcomania which can be applied to a ceramic substrate or thelike at high speed.

Another object of the present invention is to provide an improveddecalcomania which is suitable for application to ceramic objects andthe like with automatic removal of a carrier layer.

A further object of the present invention is to provide an improveddecalcomania having a bond-weakening component which facilitates theremoval of the pigment-containing layer from the carrier.

Still another object of the present invention is to provide an improveddecalcomania for application to ceramic objects and the like wherein thedecorative layer can be applied by a variety of printing processes.

Yet another object of the present invention is to provide an improvedmethod for applying a decalcomania to ceramic objects and the like, themethod incorporating the possibility of using automatic equipment forremoval of a carrier layer.

Still other objects and advantages of the invention will in part beobvious and will in part be apparent from the specification.

The invention accordingly comprises the several steps and the relationof one or more of such steps with respect to each of the others, and thearticle possessing the features, properties. and the relation ofelements, which are exemplified in the following detailed disclosure,and the scope of the invention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of theinvention, reference is had to the following description taken inconnection with the accompanying drawings, in which:

FIG. 1 is a decalcomania according to the prior art in which the carrierpaper is removed by wetting;

FIG. 2 is a decalcomania according to the prior art based on a papercarrier having a wax layer coated thereon;

FIG. 3 is a first embodiment of the present invention in which thepigment-containing layer also contains wax;

FIG. 4 is an embodiment of the present invention similar to that of FIG.3 but having an added thermoactive layer superimposed on apigment-containing layer;

FIG. 5 is an embodiment of the present invention in which a papercarrier may be removed either in the wet form or in dry form;

FIG. 6 is an embodiment of the present invention similar to that of FIG.5 but having an adhesive layer superimposed on a pigment-containinglayer;

FIG. 7 is an embodiment having a preprint lacquer containing oil betweena support layer and a pigmentcontaining layer; and

FIG. 8 is an embodiment of the present invention in which a preprintlacquer layer is readily removable from the decal paper.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical embodiment of theprior art is shown in FIG. 1 in which the decalcomania illustratedconsists of a decalcomania paper I, coated with dextrin or glue, a colorprint 2, containing vitrifiable pigments and a mask 3 to hold the colorstogether. The color print may be applied by screen-printing, off-setprinting, lithoprinting, or flat printing. The mask is applied as a thinlacquer based on a acrylic resin or ethyl cellulose or celluloseacetobutyrate. etc. In this type of construction, the decalcomania papermust be wetted to release it from the color print and the color print isthen slid onto the substrate to be coated with the color print itselfmaking contact with the substrate.

A second construction is shown in FIG. 2. A paper I has a wax coating 4thereon and the wax coating 4 is covered by a preprint lacquer 5. Thispreprint 5 coating is necessary because it has been found to beimpossible to print effectively on a wax layer. In this case, the

color print 2 is generally applied by screen-printing. Finally, colorprint 2 is covered by a mask 6 containing a thermo-plastic adhesivewhich is activatable by heat. This type of decalcomania is applied tothe substrate to be decorated with mask 6 making contact with thesubstrate. The substrate itself may be heated in which case the mask 6is activated to cause color print 2 to adhere to the substrate. A shorttime later wax layer 4 softens and decalcomania paper 1 can be removed.

Conversely, the decalcomania can be applied to a substrate and heatapplied through the carrier which in this case is a paper. Wax layer 4melts first, after which mask 6 softens causing the decalcomania toadhere to the substrate.

Although the use of wax-coated paper eliminates the need for wetting thecarrier paper 1, and although the process of application of thedecalcomania to the substrate and removal of the paper may be automated,the process is not as rapid as is desired.

The embodiment of the present invention in its simplest form is shown inFIG. 3 where a layer of decalcomania paper coated with dextrin hasprinted thereon by screen-printing a decal layer containing vitrifiablepigment with wax incorporated in the composition. The wax may be a highmolecular weight polyethylene or a high molecular weight polyglycol. Themethod of use of this particular construction is to apply the colorprint directly to the substrate and then to remove the decalcomaniapaper. This can be done either by wetting the decalcomania paper or byheating either face of the decalcomania so as to melt the wax. The waxperforms a double function in that it decreases the adhesion of thecolor print to the decalcomania and in that it melts when heat isapplied making it possible to remove the decalcomania paper in drycondition. In this type of construction, the color print can be appliedby offset or flat printing as well as by screen-printing. The followingthree examples give compositions suitable for screenprinting. In each ofthe compositions, enough pigment is incorporated so that the pigmentconstitutes from one-half to two-thirds of the total weight of the decallayer as deposited.

The dibutylphthalate in each of the compositions (Examples 48 as well asExamples 1-3) functions as a plasticizer. Any other high-boiling solventcompatible with the resin component of the specific composition willalso serve as a plasticizer or softener as is well known.

-Continued EXAMPLE 1 Parts by weight Parts by weightpolybutylmethacrylate 3 3 polyglycol. molecular weight 1 .000-3 5.000dibutylphthalate 2 solvent 55 EXAMPLE 4 Parts by weight polyethylene.molecular weight 2000-1000 ll) dibutylphthalate 2 solvent 48polyvinylacetate. molecular weight EXAMPLE 5 Parts by weightpolyethylene, molecular weight 1000-3000 2 dibutylphthalute 2 solvent 54polyvinyl-acetate. molecular weight EXAMPLE 6 Parts by weightpolyethylene. molecular weight 2.000-3.00(J l0 polybutylmethacrylate 40dibutylphthalate 2 solvent 48 EXAMPLE 7 Parts by weightpolybutylmethacrylate 4O polyglycol. molecular weight 1.0U035.U0(J Sdibutylphthalate 2 solvent 53 EXAMPLE 8 Parts by weight polyglycol.molecular weight LOGO-35.000 5 dibutylphthalate 2 polyvinylucctntc.molecular weight 1 00.000-2 000.000 40 solvent 53 As would be expectedfrom the relationship of the embodiments of FIGS. 3 and 4, dextrincoated decal paper 8 can be removed either by wetting or by heating indry condition.

Printing on decalcomania paper is a relatively difficult process.Consequently. it is desirable, as shown in FIG. 5, to interpose apreprint lacquer layer 5 between the carrier paper 1 and color printlayer 7 containing wax. This arrangement is improved by further coatingcolor print layer with adhesive layer 6 as shown in FIG. 6. The carrieris shown in both FIGS. 5 and 6 as being a decalcomania paper but itcould equally well be a foil such as aluminum foil. In both cases, thecarrier is removed from the preprint lacquer layer by means of heatapplied to either the substrate to be coated or to the carrier.

As pointed out above, each of the color print layers contains wax sothat the bond with the carrier is weak, thereby making it relativelysimple to remove the carrier. It is also possible to weaken the bondwith the carrier by using a preprint lacquer containing oil. Such astructure is shown in FIG. 7 in which decalcomania paper 1 is coatedwith preprint lacquer 9. a preprint lacquer of this type can be colorprinted by screen, offset or flat printing. Preferably, an adhesivelacquer layer 6 is also screen printed on color print layer 7.

A structure which gives particularly good results is that shown in FIG.8 in which decalcomania paper I is coated with a removable preprintlacquer layer 10, a color print including wax and a finishing varnish 6also including wax. Again, the decalcomania paper is removed by theapplication of heat to either face of the structure.

The preprint lacquers 9 and 10 may be prepared with acrylic resins asthe base and contain admixed thereto Castor oil, mineral oil or otheroils which have the property of causing the lacquer to make only a weakcon nection with the dextrin coating of the decalcomania paper. As aresult, after drying, the carrier can readily be lifted or blown off theremainder of the decalcomania structure in dry condition.

It is thus seen that the bond between the color print layer containingvitrifiable pigment and the carrier can be weakened either byincorporating wax in the color print layer or by incorporating oil in apreprint layer thereby making it feasible to separate the carrier fromthe color print layer with sufficient ease and speed so that automationbecomes possible and so that the cost of application of decalcomanias issubstantially decreased. Also, the process is suitable for use not onlyglazed ceramic but on unglazed ceramic as well.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description, are efficiently attained and,since certain changes may be made in carrying out the above method andin the article set forth without departing from the spirit and scope ofthe invention, it is intended that all matter contained in the abovedescription and shown in the accompany drawings shall be interpreted asillustrative and not in a limiting sense.

It is also to be understood that the following claims are intended tocover all ofthe generic and specific features of the invention hereindescribed, and all statemerits of the scope of the invention which, as amatter of language, might be said to fall therebetween.

What is claimed is:

l. A decalcomania suitable for application to a ceramic substrate athigh rate consisting essentially of a carrier layer, an overlying decallayer containing vitrifiable pigment and a thermoplastic resin, and anagent for facilitating the separation of said decal layer from saidcarrier layer, said agent consisting essentially of a member selectedfrom the group consisting of a wax in said decal layer and a preprintlacquer layer between said decal layer and said carrier layer, saidpreprint lacquer layer containing a quantity of oil effective forfacilitating said separation said wax being selected from the groupconsisting of polyethylene and polyethylene glycol.

2. A decalcomania as defined in claim 1, wherein said thermoplasticresin is polybutylmethacrylate.

3. A decalcomania as defined in claim 1 further comprising a finishingadhesive layer containing a thermoplastic resin overlying said decallayer, thereby causing said decal layer to adhere to a substrate whensaid decalcomania is applied to said substrate and heated to atemperature high enough to render said finishing adhesive layer tacky.

4. A decalcomania as defined in claim 3, wherein saidthermoplastic-containing layer when deposited on said decal layercomprises at least one thermoplastic resin, a plasticizer and at leastone solvent.

5. A decalcomania as defined in claim 1, wherein said decal layer whendeposited contains a pigment, a thermoplastic resin, a wax selected fromthe group consisting of high molecular weight polyethylene and high mo-,lecular weight polyglycol, a plasticizer and a solvent. 6. Adecalcomania as defined in claim 5, wherein said pigment constitutesfrom one-half to two-thirds of said decal layer by weight as deposited.

7. A decalcomania as defined in claim 1, wherein said carrier is a paperpermeable to water and is coated with glue or dextrin.

8. A decalcomania as defined in claim 1, wherein said carrier is a metalfoil.

9. A decalcomania as defined in claim 1, wherein said preprint lacquerlayer contains sufficient oil to weaken any bond between said preprintlayer and said carrier, thereby making it possible to strip said carrierfrom said preprint lacquer layer.

10. A decalcomania suitable for application to a ceramic substrate athigh rate consisting essentially of a carrier layer permeable to waterand coated with dextrin or glue, an overlying decal layer containingvitrifiable pigment, wax, and a thermoplastic resin, and a finishinglayer containing thermoplastic resin overlying said pigment-containingdecal layer, said carrier being detachable from said decal layer bywetting said carrier subsequent to attaching said decalcomania to asubstrate by heating.

1. A DECALCOMANIA SUITABLE FOR APPLICATION TO A CERAMICSUBSTRATE AT HIGHRATE CONSISTING ESSENTIALLY OF A CARRIER LAYER, AN OVERLYING DECAL LAYERCONTAINING VITRIFIABLE PIGMENT AND A THERMOSPLASTIC RESIN, AND AN AGENTFOR FACILITATING THE SEPARATION OF SAID DECAL LAYER FROM SAID CARRIERLAYER, SAID AGENT CONSISTING ESSENTIALLY OF A MEMBER SELECTED FROM THEGROUP CONSISTING OF A WAX IN SAID DECAL LAYER AND A PREPRINT LACQUERLAYER BETWEEN SAID DECAL LAYER AND SAID CARRIER LAYER, SAID PREPINTLACQUER CONTAINING A QUALITY OF OIL EFFECTIVE FOR FACILITATING SAIDSEPARATION SAID WAX BEING SELECTED FROM THE GROUP CONSISTING OFPOLYETHYLENE AND POLYETHYLENE GLYCOL.
 2. A decalcomania as defined inclaim 1, wherein said thermoplastic resin is polybutylmethacrylate.
 3. Adecalcomania as defined in claim 1 further comprising a finishingadhesive layer containing a thermoplastic resin overlying said decallayer, thereby causing said decal layer to adhere to a substrate whensaid decalcomania is applied to said substrate and heated to atemperature high enough to render said finishing adhesive layer tacky.4. A decalcomania as defined in claim 3, wherein saidthermoplastic-containing layer when deposited on said decal layercomprises at least one thermoplastic resin, a plasticizer and at leastone solvent.
 5. A decalcomania as defined in claim 1, wherein said decallayer when deposited contains a pigment, a thermoplastic resin, a waxselected from the group consisting of high molecular weight polyethyleneand high molecular weight polyglycol, a plasticizer and a solvent.
 6. Adecalcomania as defined in claim 5, wherein said pigment constitutesfrom one-half to two-thirds of said decal layer by weight as deposited.7. A decalcomania as defined in claim 1, wherein said carrier is a paperpermeable to water and is coated with glue or dextrin.
 8. A decalcomaniaas defined in claim 1, wherein said carrier is a metal foil.
 9. Adecalcomania as defined in claim 1, wherein said preprint lacquer layercontains sufficient oil to weaken any bond between said preprint layerand said carrier, thereby making it possible to strip said carrier fromsaid preprint lacquer layer.
 10. A DECALCOMANIA SUITABLE FOR APPLICATIONTO A CERAMIC SUBSTRATE AT HIGH RATE CONSISTING ESSENTIALLY OF A CARRIERLAYER PERMEABLE TO WATER AND COATED WITH DEXTRIN OR GLUE, A OVERLYINGDECAL LAYER CONTAINING VITRIFIABLE PIGMENT, WAX, AND A THRMOSPLASTICRESIN, AND A FINISHING LAYER CONTAINING THERMOPLASTIC RESIN OVERLYINGSAID PIGMENT-CONTAINING DECAL LAYER, SAID CARRIER BEING DETACHABLE FROMSAID DECAL LAYER BY WETTING SAID CARRIER SUBSEQUENT TO ATTACHING SAIDDECALCOMANIA TO A SUBSTRATE BY HEATING.